Liss, David. The ethical assassin. New York: Ballantine Books, 2006. ISBN 140006421X.

Summary: A hapless teenager, trying to raise enough money to go to Columbia University by selling encyclopedias door to door, has almost closed a deal with a couple in a trailer park when someone bursts in and murders both of his customers. The killer then strikes up a conversation with the salesman and helps him get away from the hostile local police, who otherwise might well have suspected the salesman of the crime. Despite this initial escape, the salesman quickly finds himself trapped in a network of conflicting intrigues and forced into a series of increasingly unpleasant ethical and practical dilemmas, most of them posed by the killer as opportunistic exercises in ideological reform. The twisted plot eventually unwinds into a kind of resolution that leaves the salesman changed, a wiser but deeply sadder man.